(AMD) Dual Core A64 and HyperThreading

X86-Secret ^ | April 14, 2005 | Samuel D.

[ConservativeMind]

By attentively studying the behavior of a Dual Core Athlon 64, we realized that a very interesting characteristic of the upcoming Desktop Dual Core chip from AMD was hidden...

...So, It seems that AMD chose to activate the "HyperThreading" bit on those Athlon 64 Desktop CPUs in order to profit from optimizations already done by many programmers for HyperThreading technology. This will make possible for those upcoming Athlon 64 Dual Core to also benefit from work already carried out. For now, we do not know yet if the Dual Core Opterons will also have this bit active.

[ConservativeMind]

Intel may have more to worry about than AMD's better dual-core implementation. It appears AMD has also imbued the new desktop version of these processors with HyperThreading.

This, along with early news that tomorrow's annoucement from AMD will mention the desktop and server dual-core processors, will mark a major coup.

Users will benefit while Intel's stock suffers.

[Crazieman]

Droolage.

Chipzilla is taking a beating from AMD.

[BenLurkin]

bttt

[cabojoe]

The desktop version will also fit in existing 939 pin mobos. More info about the AMD Athlon 64 X2 here: http://www.xbitlabs.com/news/cpu/display/20050413023541.html

[corkoman]

Will I be able to run Windows 98 on it?

[Crazieman]

Yeah, but why would you want to?

If you buy the chip, why not get XP-64?

[cabojoe]

I suppose, but Windows XP 64 is due for release, why not make the most of it.

[A CA Guy]

Yes, but you must F-Disk it first.

[ConservativeMind]

If Windows 98 can run on it (which I assume it can), it will not handle the second core. It may be possible HyperrThreading from one processor could work, though.

I believe XP Professional is needed for anything related to multiple cores or more than one processor (up to two).

[ConservativeMind]

Actually, HyperThreading shouldn't work either.

Windows 98 never supported it.

[cabojoe]

ping

[dennisw]

I **ONLY** buy AMD! I've bought three Athlons/Durons so far. My next buy will be from NewEgg, will be a mobile 45watt Athlon 2500+ I'll overclock on my Shuttle board.

AMD has aced out Intel as far as power consumption. The AMD chips of the least two years run cooler that the Intel equivalents

[dennisw]

Chipzilla is taking a beating from AMD.

Serves 'em right to suffer

[scab4faa]

Will I be able to run Windows 98 on it?

And you would want to torture yourself why?

Running W98 is like buying a Pinto and driving it in reverse on the street.

[Abcdefg]

Various Unix versions should get a boost from this chip, too.

[Paul C. Jesup]

I believe XP Professional is needed for anything related to multiple cores or more than one processor (up to two).

Actually there have been dual-CPU motherboards for years. It deals more with how the motherboards bios handles the data processing than the operating systems.

Also, AMD 64 CPU are legacy compatiable with 32 bit bases operating systems, W2K for example, so in theory it should work with an older older operating system.

[Boundless]

> It appears AMD has also imbued the new desktop version
> of these processors with HyperThreading.

Well, yeah, but ...

a. Intel HT has been useless (or even a performance hit)
for the majority of users. Intel has hyped it to little
avail. Is there any reason to suppose AMD's is more
beneficial?

b. My understanding was that on AMD, DC is enabled using
the same bit that Intel uses for HT (which cleverly
avoids having to wait for always-late Microsoft for
specfic DC support). So how is this new pseudo-HT enabled?

c. And if always-enabled, does it screw up CPU counts
for MS licensing restrictions?

[ConservativeMind]

I believe the article mentions two bits, one for HyperThreading (bit 28) and the other for dual-core (bit 23).

Although HT has delivered mixed results for Intel, it is still a marketing coup just as HT was for Intel.

It is also possible the HT on the AMD chips is better implemented. They've had more time to fashion it.

[ConservativeMind]

I would disagree with your BIOS suggestion.

Operating systems must have explicit support for anything beyond one processor regardless of BIOS support. Of course, BIOS support must be there, though.

Just as with the old 80387 co-processor, extensions were necessary within the OS or a special assembly routine would be necessary to bypass DOS.

Having dual CPU motherboards never means having an OS's support for it. Without the OS support, the extra processor is effectively "lost".

[Nataku X]

I run Win2K fine with my dual Xeons. XP is admittedly a better product in some respects; after all, when my old video card suffered its occassional crash, XP caught the infinite hardware loop, shut down the video card, and didn't freeze like Win2K did. However the bloatware is getting so annoying--WinXP on a 2 gHz machine runs no faster than Win98 on a 500 mHz machine. I'm making my stand on Win2K and sticking with it as long as possible.

Also, hyperthreading worked fine with my Win2K system when I had it enabled. It saw 4 processors just fine.